STANDARD SC.912.L.16.13_Describe the basic anatomy and physiology of the human reproductive system. Describe the process of human development from fertilization to birth and major changes that occur in each trimester of pregnancy.
Students will:
A) Students will identify and/or describe the basic anatomy and physiology of the human reproductive system.
A) Students will identify and/or describe the basic anatomy and physiology of the human reproductive system.
- male: seminal vesicle, prostate gland, vas deferens, urethra, epididymis, scrotum, penis, and testes
- female: ovaries, oviduct (fallopian tube), uterus, cervix, and vagin
- changes in each trimester are limited to normal human development
- function of the placenta, umbilical cord, amniotic sac, and amniotic fluid are limited to how these structures relate to the development of the fetus.
The Male Reproductive System
MALE
- Penis: the male organ of sexual pleasure, reproduction, and urination
- Scrotum: a sac-like pouch in the groin that holds the testes and regulates their temperature
- Epididymis: Crescent-shaped structure located above each testes. Sperm coming from the testes matures here, and then goes to Vas deferens.
- Prostate Gland: Structure that produces an alkaline fluid that aids sperm longevity
- Testicles/Testes: two male reproductive glands that secrete the male hormone testosterone and produce sperm inside the seminiferous tubules.
- Seminal Vesicles: two small glands at the ends of each vas deferens that secrete seminal fluid (semen), an alkaline fluid rich in fructose, a sugar nutrient that is a source of energy for sperm. This alkaline fluid balances the acid environment of the vagina.
- Urethra: Tube that travels from the bladder through the penis and carries semen and urine, although not at the same time.
- Sperm: a male reproductive sex cell or gamete, produced by the testes and containing only half the genetic material (23 chromosomes, thus a haploid cell)
- Semen: sperm containing nourishing fluid produced by the seminal vesicles, the prostate gland and bulbourethral gland.
Can you recall the names from memory?
The Female Reproductive System
FEMALE
- Vagina: a muscular passageway that lies between the bladder and the rectum. It serves as the female organ of intercourse, the birth canal, and the passageway for the menstrual flow and the arriving sperm, It also produces fluid for lubrication.
- Cervix: the lowest and narrow neck of uterus that connects with the vagina. Produces mucus for sperm movement.
- Fallopian Tubes or Oviducts: tube that extends from near the ovaries to the uterus, this is where fertilization of the ovum by the sperm occurs
- Uterus: organ that prepares each month to receive a fertilized ovum, to support the fertilized ovum during pregnancy, and to contract during childbirth to help with delivery. This is where implantation occurs.
- Ovaries: two almond-shaped female sex glands that produce ova and secrete hormones
- Ovule/ Ovum/egg: a mature female reproductive sex cell or gamete, produced by the ovaries and containing only half the genetic material of the mother (23 chromosomes), thus is a haploid cell.
Stages of Human Development
Fertilization & Early Development PowerPoint Review
Fetal Development Stage by Stage (baby center)
Stages of Human Development Tutorial
Fetal Development Stage by Stage (baby center)
Stages of Human Development Tutorial
Human development is divided into 3 trimesters.
- What are the major events from fertilization to birth that take place during pregnancy?
1st Trimester ( Weeks 1 - 12)
The first trimester of human development is the stage of greatest change and differentiation. It is the main period of organogenesis- formation of organs.
It begins with fertilization.
It begins with fertilization.
- Fertilization is the union of a sperm cell and an egg cell to form a zygote. The zygote is a single diploid cell container the genetic material of both the father and mother.
- Fertilization occurs in upper third of Fallopian tube (closer to the ovary)
- Only 1 sperm can fertilize an egg
- The zygote now moves down the fallopian tubes towards the uterus.
What happens after fertilization?
- The zygote divides several times by mitosis to form a hollow ball of cells called a morula - a solid ball of about 16 cells.
- More cellular divisions result in a blastocyst, a ball of cells with a large fluid cavity.
- Blastocyst burrows into the lining of the uterus during implantation, and development continues.
- After the implantation of the blastocyst, the placenta begins to develop. The placenta is the organ attached to the walls of uterus that connects to the developing embryo through the umbilical cord. It acts as a lifeline nourishing the developing embryo. It is the embryo's organ of respiration (gas exchange), nourishment (nutrients for growth and development), end excretion (toxic wastes produced by the embryo are disposed via the placenta).
- All nourishment and oxygen, come from the mother's blood, and diffuse to the umbilical cord through the placenta.
- The embryo develops within the amniotic sac, the fluid-filled sac that contains and protects the fetus in the womb.
- The fluid inside the amniotic sac is called the amniotic fluid, a yellow, clear fluid that surrounds the embryo. The amniotic fluid has important protective functions: it cushions and protects the developing embryo from blows coming to the uterine area, it helps maintain constant temperatures, an the fetus swallows the fluid, it helps develop its digestive system.
- by the end of the first month the embryo has a heartbeat, brain and spinal cord.
- by the end of week 8 the embryo develops into a fetus. It can be recognized as a human, it has started the formation of arms and legs, fingers and toes.
- as time goes, the head grows larger, and neural development continues. The heart beats stronger, the mouth opens and closes, and it starts to kick, although it is so small that the mother cant' feel the movement.
- By the end of the 1st trimester, the embryo has vital organs such as heart, brain, kidney, liver, intestines.
2nd Trimester (weeks 13 - 27) |
3rd Trimester (weeks 28 - 40) |
The second trimester is a period of growth and refinement.
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The third trimester is the period for final preparations.
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What cellular processes make it all happen?
- Growth or the increase in the number of cells.
- Development or the arrangement of the cells into specific organs.
- Differentiation or the specialization of cells to perform specific tasks and functions.